WELCOME to purgatory. No, not the one they talk about in church. This one is the product of the fertile mind of a teenage girl.

She’s Celeste Davis, who at age 15 has already written and starred in a feature film, “Purgatory House,” which makes its world debut this week at the Woodstock Film Festival.

Davis plays Silver Strand, a lonely teen who commits suicide. When it comes time to meet God, He/She turns out to be a drag queen (played by Tom Hanks’ brother Jim).

Since suicide is a no-no, he sentences bleached-blonde Silver to spend eternity in Purgatory House. There she’s doomed to remain 14 forever and to watch her family and friends going through life without her.

So why is her God a drag queen?

“I didn’t know what God was. Would God be a man? Would God be a woman? Why not make God a man dressed like a woman?” the California high school student explained via e-mail.

Celeste admits that part of the script is autobiographical – “except that Silver is a more extreme version of who I am.

“A lot of the flashbacks are based on my own life. I really wanted to show how drugs are just everywhere in school. You cannot get away from it, even if you want.”

The movie’s director/producer is Cindy Baer, who four years ago was matched with Celeste – the product of a dysfunctional family – through the Big Sisters of Los Angeles, which pairs “at risk” girls with female mentors.

Celeste said the idea for “Purgatory House” came when “I was cleaning my messy bedroom one night.

“I hated cleaning, and I thought how horrible it would be after you died to get stuck doing over and over all the things you hated back on earth.

“Or worse, to be 14 forever. To never grow and change. To never learn or find a way to be happy.”

“Purgatory House” is one of 130 features and shorts unreeling at the fourth edition of the Woodstock fest.

It kicks off Wednesday and runs through next Sunday, with screenings in the upstate hippie haven and in nearby Rhinebeck, Hunter and Mount Tremper.